Right Camera And External Flash?

Hi I am am amateur photographer still trying to get to grips with all the jargon used and trying to get to grips with my camera.I love to take pictures of my son and friends and family and brought a canon D400 off a friend cheap would you suggest this is a good camera for this as it only comes with a 18-55mm lens and not sure if I need to upgrade the lens?

Also am about to go on holiday and keep hearing about external flashes but don't know very much about them and if it would be benefical for me to buy and take one to lanzarote with me to get better results?Hope your able to give me some advice sorry for complex message.Jenny

Normal N73 and N73 Music Edition have almost the same functions. You might ask yourself what makes them different? N73 Music Edition provides a 2GB miniSD, an easy button access to music player, 3.2mega-pixels camera and best of all; its design is in a captivating Black stylish outer appearance.